1. Field of the Invention
The present invention relates generally to wire nails and methods of manufacturing wire nails, and more specifically to wire nails that can be densely collated into strips for use in nail-driving tools.
2. Description of Related Art
To facilitate the use of wire nails by pneumatic or electrically powered nail-driving tools, wire nails are typically linearly collated using adhesively applied tapes or other known collating media (e.g., welded connecting wires, glue, etc.) to form strips that can be easily inserted into and used by such nail-driving tools.
Dense collation is preferred to provide the maximum number of nails in the least space. Unfortunately, conventional, full-round head nails (nails having heads with circular cross-sections) with centered heads and shanks cannot be positioned with shanks in parallel, shank-to-shank contacting relation because the heads of adjoining nails interfere with their shanks being disposed in such manner. Various types of wire nails have been developed to resolve this shortcoming. For example, strips of collated wire nails having D-shaped heads are exemplified in Lingle (U.S. Pat. No. 3,152,334), Leistner (U.S. Pat. No. 3,861,526), Shelton et al. (U.S. Pat. No. 3,966,042), and Powers (U.S. Pat. No. 3,359,582). Shanks of such nails abut the flat edge of the D shape of adjoining nail heads such that dense shank-to-shank collation is possible. Other similar head shapes may also be used to enable shank-to-shank collation. See, e.g., Julifs (U.S. Pat. No. 2,940,081) and Becht (U.S. Pat. No. 3,481,459).
Unfortunately, such D-shaped or variant-shaped heads have their own disadvantages. For reasons of aesthetics and performance, it is highly desirable to have nail heads that are full-round. In addition to the inferior aesthetics and performance, D-shaped or variant-shaped heads are more difficult to manufacture than full-round heads. None of the D-shaped or variant heads disclosed in the foregoing patents has a full-round (complete circle) head when viewed along the longitudinal axis of the shank.
Various wire nails have been developed in an effort to balance the advantages of D-shaped/variant-shaped nails with the advantages of full-round head nails. O'Connor (U.S. Pat. No. 3,358,822) and Sygnator et al. (U.S. Pat. No. 5,056,976) disclose full-round head wire nails with heads that are radially offset from their shanks (hereinafter “offset-head nails”). This offset head reduces the degree to which the head of the nail overhangs the shank and improves lateral nail density. Although the overhang is reduced, it still results in gaps between adjoining collated nails. These gaps limit lateral nail density and prevent shank-to-shank collation.